Kristin Cavallari wants to gain weight after losing more than 20 pounds shortly after giving birth to her second child. Cavallari, who credited a low-carb Paleo-style diet for her 20-pound post-baby weight loss, admits she's too thin now.

"Because I have no curves, I can look really skinny and I don't like that," Kristin told E! Jan 22. "So I'm drinking protein shakes, I'm trying to put on muscle and I'm lifting very heavy weight right now."